Civil Enginerring

• Name: Oliver Hutchinson • Date: 21.01.22• Student Number: 5242110 • Course: HNC Construction and the Build Environment • Unit name: Unit 02 Construction Technology• Assessment Title: Civil Engineering

(pixabay, 2022)

Civil Engineering

PG 1 ...... Brownfield Sites PG 2 ...... Site Remediation PG 3&4 ...... Civil EngineeringPG 5&6 ...... Building Frames

Contents

(pixabay, 2022)

Land HistoryThe history of the land usage can be a good indicator of what is likely to be found in the ground. This can be found by land registry records or via a site investigation as outlined in pamphlet 1.For example, if there was a garage on the land, you could assume there may be some petrol or oil that was spilt at some point, so you are likely to find this in the ground. The desk study will only tell you the documented history of the land, a site investigation can provide the detailed information regarding the ground condition and contamination levels. An example ofBbrownfield site hazards are:

• Threats to human health.
• Damage to flora and fauna.
• Contamination of ground water.
• Damage to foundations and structures.
• Settlement.
• Subsidence.
• Migration of contaminants to adjacent land.

Brownfield land is categorised into 4 types; • Vacant • Derelict • Contaminated • Partially occupied or utilised

Why use Brownfield? In 1998 the government set a target on brownfield land to specify that 60% of all new developments were to be on brownfield sites to combat a rise in derelict land/properties and to stop urban sprawl. The NPPF however does not mention any % of brownfield land to be used specifically but does comment that it encourages the use of brownfield land. Because of this in 2010 it was estimated that 76% of new buildings/developments were on brown field land.

As set out by the National Planning Policy, there are two types of land; Greenfield and Brownfield.A Greenfield site is described as a "virgin site" meaning it has had no prior buildings or construction work on it. A Brownfield site has been occupied previously by a permanent structure of some description.

Brownfield Sites

(pixabay, 2022)

Thermal Treatment Thermal treatment involves using heat to remove the organic contaminants. This is carried out by a vacuum system that delivers heat to remove all moisture and organic matter from the desired area.

Physicochemical Treatment Physicochemical treatment includes electric resistance heating, soil flushing, chemical oxidation, soil vapour extraction (SVE), fracturing, solidification and stabilisation. pH adjustors, soil protection, organic amendments are also types of soil treatment

Biological Treatment Bioremediation treatment - This is a way of biodegrading the contaminant by using bacteria and microorganisms that attack the contaminant.Biostimulation - This involves calculating how to stop the contaminant via a natural degrading process. For example and organism that lived deep in the soil could be sensitive to high oxygen levels, so then a way to increase the oxygen level at that depth would increase the degrading process.Bioaugmentation - This involves adding a different bacteria that will counteract the contaminant, This is quite complex as you need to find an bacteria that can live in the conditions required but will also be a passive bacteria once it irradicates the contaminant.

Land Fill This involves excavating the contaminated materials and sending it to a registered tip that can treat the material to neutralise the contamination before it goes to land fill. There are three main categories for excavated material on site. Inert – Meaning the material is clear of contaminants and suitable to be re-used or go to land fill. Non-Hazardous – Meaning the material is not clear of all contaminants but the material is not harmful to human health and can go in to land fill without treatment but the landfills are a lot more regulated and fewer and further between meaning the cost is higher than inert to remove. Hazardous – This is the type of material that needs specialist treatment before the mater can be used for landfill. This can contain a multitude of contaminants such as, petrol, oil, asbestos. Once the contaminants have been identified when excavating every level of care must be taken when excavating the material. When excavated is put straight on to plastic sheeting or tarpaulin which acts as a barrier to the cleaner material this will avoid and seepage or cross contamination.

In order to build to on a Brownfield site, the site may require remediation, meaning to reverse the effect of the previous work and return the land to a natural, uncontaminated state prior to carrying out and construction works. The remediation of contamination can be fairly complex to manage, especially if you have more than one contaminant across the land. Once you have the site investigation you will be able to formulate a plan of action on how to deal with the contamination from the following options.

Site Remediation

(pixabay, 2022)

Types of civil engineer: 1. Construction engineering 2. Environmental engineering3. Earthquake engineering 4. Structural engineering 5. Geotechnical engineering6. Water resources engineering 7. Fire protection engineering 8. Transportation engineering

Civil engineering is the specialist field in which they conceive, design, build, supervise, operate, construct and maintain infrastructure and sub structure projects and systems.

Civil Engineering

(pixabay, 2022)

(pixabay, 2022)

When construction takes place, it will be a civil engineer that will build the infrastructure to the project. They construct the roads and footpaths which involves liaising with the local authorities to gain road closures or diversions to enable the new road to connected to existing road networks. Civil engineers will also install the mains drainage both foul and storm. Main line drainage is usually installed under the road and then routes run away from this up to the building, it is usually adopted (become responsibility of) the local authority up to the inspection chamber outside of the property. Anything past that is then classed as private drainage which is then the responsibility of the property owner. It is essential that civil engineers have a detailed knowledge of the expectations and specifications of the authorities they are working within as each different authority will specify there own wants and needs.

Roads and Sewers

The overall construction of a basement requires the deep excavation of the ground, which in turn will lead to the requirement of ground shoring to stop and ground collapse or slippage and dewatering the excavation as the water will interfere with the construction and causes a potential hazard.

Box and cellular raft basement - These are very similar to the above except they have internal walls to separate the basement into separate rooms. These internal walls are the load bearing walls. Piled Basement. The superstructure loads are caried through columns and then are transmitted through to the piles. The piles are installed and acts as explained in the piled foundations section of the foundation pamphlet

BasementsBasements require specialist knowledge and expertise to build. Due to them being built within the ground, calculations must be made to establish the ground pressure the height of the water table This will then determine the method of construction, the three types being;Raft and retaining wall basement – This type of basement consists of a raft slab foundation, retaining walls and a suspended slab roof. The floor helps distribute structural loads down through the retaining walls.

Civil Engineering

(pixabay, 2022)

Column formwork varies from, but is used in conjunction with beam formwork as the columns are formed vertically, whereas the beams a horizontal. This is done by sheets of ply wood being supported by timber cleats which act as a bracing to withstand the hydrostatic pressure of the wet concrete. This is placed where the column is to be installed around reinforcement steel which will run through the centre of the concrete. As per above explanation the concrete is poured in and let to set. The columns created via this method are the load bearing columns that will carry the buildings loads down to the foundation. Reinforcement steel is required for concrete frames as concrete has very little tensile strength, when the concrete is poured and is still wet a vibrating poker is put into the concrete which vibrates to drive any air out. This is to avoid any air pockets which would weaken the structure.

Beam formwork in essence is a three sided box with bracing struts to the sides to support the hydrostatic pressure of the wet concrete, with the bottom being capable of supporting the weight of the concrete until it has set and is able to support its own weight. A non-bonding coating is then applied to stop the concrete from sticking to the formwork. The concrete is poured into the top of the formwork to the desired level and once the concrete has been poured, it is left to set, the setting time will vary on many factors, the temperature, weather, concrete type. The beams created by doing this method are usually the floors of the building.

Concrete. The difficulty of constructing a frame from concrete is the natural state of concrete is liquid, so the difficulty comes in keeping the concrete in place long enough for it to set. This is done by using formwork. Formwork can be fabricated on site with timber plywood, there are systems available made from steel or aluminium which can be bought or hired form a shoring company. Formwork comes in two types

There are two main types of building frames Cast in-situ and steel.

Building Frames

(pixabay, 2022)

Building Frames

Steel frames Structural steel can be used to build the skeleton of the building. Steel structures offer a wider choice of manufacture, You can have the structure pre-fabricated and welded into sections, this is then delivered to site and the sections are bolted together to form the entire structure, or you can have each part prefabricated and delivered to site to be bolted or welded on site by the contractor. The vertical columns are bolted to the foundation these are the weight bearing columns, cross beams are then bolted between the columns to add structural integrity and to stop any movement or twisting of the structure.This is usually built using hot rolled steel, which is the process of heating up the steel to soften it enabling it to be manipulated int the required shape. and is common in high-rise, industrial and commercial buildings. A steel frame needs to be covered with some kind of heat protection as any exposure to heat can cause bending or warping . The kind of protection needed can be either cladding masonry, plaster board or concrete as these have either a natural heat resistance or a an element of flame retardant is added during the manufacturing stage.

Another point to note when comparing steel and concrete frames is the consideration of the installation of both the primary and secondary elements of the building as well as services , things such as the doors and windows. Within a concrete structure, these elements must be designed into to construction as once building is completed it is very difficult to move or alter as they may be within a load bearing section of the structure so the structure would have to have props installed to carry the load, a lintle must be added above any new opening made to counteract the weight displacement from the opening created. In a steel structure, It is altogether easier to alter these, as you are altering the cladding and may need to move one of the cross steels but as these are not load bearing the can be moved or altered to suit any change in use or purpose with very little difficulty.

Concrete Frame

Below is a list of positives and negatives for both steel and concrete framed buildings

Steel Frame

Building Frames